Section 5 Crew Requirements

Transcription

1 Section 5 Crew Requirements Panel Fabrication After the home s design has been approved by the client and permitting agencies, Nexframe will begin production according to the construction schedule. The steel studs and tracks are manufactured using Nucon s proprietary rollformers and software. Each rollformer has a computer monitor that displays the panel being produced and indicates where each steel member goes. The rollforming software is integrated with the engineers design software to facilitate panel modifications and layout changes. The wall panels are fabricated on either floor jacks or a framing table, as pictured here. A panel fabricating crew consists of either three or four individuals and takes only a few minutes to fabricate one panel. Wall panel fabricators in the plant also help with roof truss production, conversely truss fabricators help with wall panel production as needed. Completed wall panels are stored on the transportation trailers until delivery. One fabrication crew can produce one floor of wall panels per day. To avoid excessive on-site storage a just-in-time production schedule is developed to limit storage at the construction site and production facility. Wood door and window jams are installed in the plant. Wood components are cut to length at the fabrication plant and stored in bins according to length. When the plans call for a wood jam, a fabrication crew member installs the appropriate piece from the bin. During the design phase, many of the window and door openings are standardized to limit sizes of wood door jams to increase production efficiency. Roof Truss Fabrication Roof trusses are fabricated in a similar sequence as wall panels. However, the truss fabrication crew prefers to use floor jacks for framing over the framing tables, because the floor jacks can be quickly adjusted to the changing shapes of trusses. Exposed wood rafter tails as shown to the right are common in the California housing market and are applied at the production facility. The rafter tails are attached with screws once the truss is completed. Just like window and door jams, wood rafter tails are cut at the fabrication facility and stored in bins near the truss fabrication area. 15

2 Fabrication Labor Nexframe has four distinct crews each consisting of four individuals. There are also three management level production employees. The fabricating crew salaries range from $10 to $14 an hour, management salaries are competitive for the region. Laborers must be capable of reading plans and are expected to have an associate degree or two to three years of framing experience. Fabricating crew members typically work in their assigned task area, however; Nexframe does promote cross-training to handle peak production times. The Inventory Manager also works on the fabrication floor when needed. There is only one shift, during the day, at Nexframe s production facility. Framing The framing crew is responsible for all tasks associated with installing the wall panels and trusses. The observed homes are single story slab foundation homes, ranging from 1,200 to 1,400 square feet. The first floor wall panels took a day and a half to install, the roof trusses took about a day to install, and the roof took about a half day to sheath. The following is a brief overview of the framing crew tasks for the observed construction project. Foundation Prep The foundation slab was poured by another contractor, who also installed the wet-poured anchor bolts. The anchor bolts are used to secure the panels to the foundation. The framing crew places chalk lines on each slab to facilitate panel placement. Unloading Panels are stored on the transportation trailer until they are needed. Framers only unload a panel when it is going to be installed. Panels are typically moved by three individuals. Standing Wall Panels A panel is carried over to the foundation, stood up and temporarily secured to the foundation with nails and washers and braced, as needed, with steel studs. The wall panels vary in length, depending on location, but are not longer than twenty 16

3 feet. The studs at the Lennar site are 2x4s spaced at twenty-four inches oncenter. The steel s thickness depends on the calculated loads, but will be either 33 or 43 mils. The panels exterior was covered with one inch thick foam insulation and a stucco finish, both installed by the stucco contractor. Anchoring The panels are permanently anchored to the foundation using the wet poured Hilti 1/ ¼ inch length bolts. This process is performed once all the panels are in place. Support Beam A support beam is installed across the opening of the garage by the framing crew once the panels are secured to the foundation. Roof The truss installation and sheathing tasks take about 1-1/2 days to complete. Roof sheathing is attached to the trusses using ETF pins. Once all the roof sheathing is secured, the soffits and fascia boards are installed by the framing crew with ETF pins. Windows The windows and weather barrier tape were installed by Lennar s framing crew. Because Nexframe fabricates steel panels with wood jams, the windows were fastened to the frame using nails. Interior Walls The interior wall studs and tracks arrive cut to length and are stick-built by the framing crew. The studs and tracks are 43 mil for an interior load bearing wall or 33 mil for an interior partition wall. Drywall is attached using screws. The roof sheathing is OSB. The fascia is wood 2x6s and the soffit ½ inch plywood. All roof sheathing material was supplied by Nexframe. These homes will be covered with tile, which is supplied and installed by a separate subcontractor. 17

4 Stucco The framing crew is not responsible for the applying the stucco or one inch exterior foam. A separate contractor has been hired to apply the homes exterior finish. Framing Labor The framing crew was hired by Lennar but framers wages and hours are determined by their individual employer. The labor rates for the crew are as follows: foreman at $50 per hour, lead carpenter at $47 per hour, and the three apprentices at $35 per hour each. These labor rates include payroll taxes and benefits paid by the employer. The framing crew had previous experience framing homes with wood but had less than one year of steel framing experience. However, the construction supervisor had over three years of steel framing experience. The framing crew worked one shift, 7:00 a.m. to 3:30 p.m., five days a week. Framing Process The framing crew works as a group when installing wall panels and trusses. The crew works individually on other tasks to improve efficiency. During the observation three homes were in various stages of the framing process. Framing Innovations One of the biggest benefits of engineered steel wall panels is the ability to adjust steel thickness to maximize a home s strength while minimizing material costs. Nexframe incorporates premanufactured braced wall sections into home designs to provide the necessary shear value. The sections are purchased from a third-party provider and are integrated into the specified wall panels at the fabrication facility. This eliminates the need for OSB sheathing. The transportation of steel wall panels is an important factor in maintaining a construction schedule and limiting damage. Nexframe has experimented with numerous transportation methods and has found a custom flat-bed trailer to be the most efficient method. The wall panels are fabricated in an order that results in the first wall panel to be installed will be the last panel produced 18

5 and placed on the trailer. This way the builder can safely store panels on the trailer instead of unloading all the panels, if necessary. When the next trailer of panels is delivered, the driver returns to the to fabrication facility with an empty trailer from a previous delivery. The Westgate Estates subdivision has a zero-setback, resulting in very little room for storage in the yard. The trailers are parked on street in front of the home; the framing crew then unloads a panel one at a time when needed. 19